Single-channel properties of IKs potassium channels.
Single-channel properties of IKs potassium channels.
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DOI：
10.1085/jgp.112.6.665
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发表时间：
1998-12
期刊：
影响因子：
--
通讯作者：
Sigworth FJ
中科院分区：
文献类型：
--
作者：
Yang Y;Sigworth FJ
在非洲爪蟾卵母细胞中表达的KvLQT 1通道亚基产生小的、快速激活的、电压依赖性的钾电导。当与minK基因产物共表达时，产生缓慢激活且大得多的钾电流。使用波动分析和单通道记录，我们已经研究了由人KvLQT 1亚基单独和与人或大鼠minK亚基结合形成的电流。在外部K+较低的情况下，基于+50 mV电流的20 kHz带宽下的噪声分析，这三种通道类型的单通道电导估计分别为0.7、4.5和6.5 pS。在0.1 Hz-20 kHz范围内计算的功率谱显示出弱的频率依赖性，与在宽范围的时间尺度上发生的电流中断一致。宽谱导致表观单通道电流值取决于记录的带宽，并且反映在来自共表达的KvLQT 1和人minK亚基的通道的非常“闪烁”的单通道事件中。由于存在的minK亚基的宏观电流的增加是由增加的表观单通道电导，它赋予表达的通道占。大鼠minK亚基还赋予外向单通道电流被外部钾离子增加的性质。
Expressed in Xenopus oocytes, KvLQT1 channel subunits yield a small, rapidly activating, voltage- dependent potassium conductance. When coexpressed with the minK gene product, a slowly activating and much larger potassium current results. Using fluctuation analysis and single-channel recordings, we have studied the currents formed by human KvLQT1 subunits alone and in conjunction with human or rat minK subunits. With low external K+, the single-channel conductances of these three channel types are estimated to be 0.7, 4.5, and 6.5 pS, respectively, based on noise analysis at 20 kHz bandwidth of currents at +50 mV. Power spectra computed over the range 0.1 Hz–20 kHz show a weak frequency dependence, consistent with current interruptions occurring on a broad range of time scales. The broad spectrum causes the apparent single-channel current value to depend on the bandwidth of the recording, and is mirrored in very “flickery” single-channel events of the channels from coexpressed KvLQT1 and human minK subunits. The increase in macroscopic current due to the presence of the minK subunit is accounted for by the increased apparent single-channel conductance it confers on the expressed channels. The rat minK subunit also confers the property that the outward single-channel current is increased by external potassium ions.
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影响因子：
3.4
作者：
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通讯作者：
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作者：
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